Dual Stack Mobile Internet Protocol (DSMIP) is based on Mobile IP (MIP) protocol that was developed to enable mobility of IP clients between IP subnets (with different address prefixes or IP address pools) without having to change the IP address. In addition to the basic mobility functionality of MIP, DSMIP allows support for IP version 4 (IPv4) and IP version 6 (IPv6) protocol stacks. MIP and DSMIP were standardized in the Third Generation Partnership Project (3GPP) and 3GPP2 for handovers with IP address preservation, that may be referred to as seamless handovers.
Proxy Mobile IPv6 (PMIPv6) is an alternative solution to DSMIP, designed to support IPv6 nodes without any new IP level mobility signaling involvement of the mobile node (MN) by extending, with some modifications, the MIP version 6 (MIPv6) protocol signaling messages between a network node and a home agent (HA), (which in PMIP is referred to as “local mobility anchor” (LMA)). This approach does not require the MN to be involved in the exchange of signaling messages between itself and the HA. In PMIPv6, a proxy mobility agent in the network, (i.e., the mobility access gateway (MAG)), performs the signaling with the LMA and performs the mobility management on behalf of the MN attached to the network.
If the MN simultaneously connects to the PMIPv6 domain through multiple interfaces (and through multiple MAGs), the network allocates a unique set of home network prefixes (HNP) for each of the connected interface. The MN configures addresses on those interfaces from the respective HNP.
If the MN performs a handoff by moving its address configuration from one interface to another, and if the LMA receives a handoff hint from the serving MAG, the LMA may assign the same HNP that it previously assigned prior to the handoff. The MN may perform a handoff by changing its point of attachment from one MAG to another using the same interface and may retain the address configuration on the attached interface.